Galvanic cells Knowledge-Based Practice

Questions

1. 1.

   In a galvanic cell where a half-cell reaction involves only dissolved ions, such as the reduction of $\text{Fe}^{3+}(aq)$ to $\text{Fe}^{2+}(aq)$, what is the essential function of an inert electrode like platinum?

   • A) It oxidizes spontaneously to supply electrons directly to the dissolved cations.
   • B) It provides a conductive physical surface for electron transfer without undergoing chemical change.
   • C) It functions as an internal salt bridge that balances electrical charge between the half-cells.
   • D) It acts as a homogeneous catalyst that alters the standard reduction potential of the half-reaction.
2. 2.

   According to IUPAC conventions, which cell notation correctly represents a standard galvanic cell based on the spontaneous reaction $\text{Mg}(s) + \text{Cu}^{2+}(aq) \rightarrow \text{Mg}^{2+}(aq) + \text{Cu}(s)$?

   • A) $\text{Cu}(s) \mid \text{Cu}^{2+}(aq) \parallel \text{Mg}^{2+}(aq) \mid \text{Mg}(s)$
   • B) $\text{Mg}(s) \mid \text{Mg}^{2+}(aq) \parallel \text{Cu}^{2+}(aq) \mid \text{Cu}(s)$
   • C) $\text{Mg}^{2+}(aq) \mid \text{Mg}(s) \parallel \text{Cu}(s) \mid \text{Cu}^{2+}(aq)$
   • D) $\text{Mg}(s) \mid \text{Cu}^{2+}(aq) \parallel \text{Mg}^{2+}(aq) \mid \text{Cu}(s)$
3. 3.

   A standard galvanic cell is constructed using the $\text{Sn}^{2+}/\text{Sn}$ ($E^\circ = -0.14\text{ V}$) and $\text{Fe}^{2+}/\text{Fe}$ ($E^\circ = -0.44\text{ V}$) half-cells. What is the standard cell potential of this cell, and which electrode acts as the cathode?

   • A) +0.58 V, with Fe acting as the cathode
   • B) +0.30 V, with Sn acting as the cathode
   • C) +0.30 V, with Fe acting as the cathode
   • D) +0.58 V, with Sn acting as the cathode
4. 4.

   A standard galvanic cell is assembled using a nickel electrode immersed in a 1.0 M nickel nitrate solution and a silver electrode immersed in a 1.0 M silver nitrate solution, connected by a salt bridge. Given that the standard reduction potential is +0.80 V for the silver half-cell and -0.25 V for the nickel half-cell, which change occurs as the cell discharges?

   • A) The silver electrode functions as the anode, and its mass decreases.
   • B) Electrons flow through the external wire from the silver electrode to the nickel electrode.
   • C) The concentration of nickel ions in the anode half-cell solution decreases.
   • D) The nickel electrode acts as the anode, and its mass decreases as oxidation proceeds.
5. 5.

   In an operating standard zinc-copper galvanic cell connected by a salt bridge containing potassium nitrate, which statement correctly describes the movement of charge carriers?

   • A) Anions from the salt bridge migrate toward the zinc half-cell, and electrons flow through the external circuit from the zinc electrode to the copper electrode.
   • B) Cations from the salt bridge migrate toward the zinc half-cell, and electrons flow through the external circuit from the zinc electrode to the copper electrode.
   • C) Anions from the salt bridge migrate toward the copper half-cell, and electrons flow through the salt bridge from the zinc electrode to the copper electrode.
   • D) Cations from the salt bridge migrate toward the copper half-cell, and electrons flow through the external circuit from the copper electrode to the zinc electrode.

Answers and step-by-step solutions appear after you finish the test.